Bleaching compositions containing a n-acyl azole

ABSTRACT

A dry oxygen bleaching composition which is useful at relatively low water temperatures is provided. The composition contains a hydrogen peroxide releasing compound and an activating amount of an N-acyl azole of the formulas:   WHEREIN R1 individually is hydrogen, alkyl, halogen or nitro; R2 can be a wide variety of substituted or unsubstituted alkyl, alicyclic or aryl radicls; A is a mono- or di-substituted or unsubstituted 6-membered aromatic or N-heteroaromatic ring having 1-4 nitrogen atoms; and x and y are individually selected from nitrogen and C-R1, and at least one of x and y is nitrogen. A typical composition is a mixture of sodium perborate and N-acetyl imidazole in a 1:1 mol ratio.

United States Patent [191 Fine et al.

[ 1 BLEACIIING COMPOSITIONS CONTAINING A N-ACYL AZOLE [76] Inventors: Leonard Wolfe Fine, 15 Grey Hollow Rd, Norwalk, Conn.; Martin Grayson; Virginia Suggs Grayson, both of 91 Strawberry Hill Ave., Stamford, Conn. 06902 [22] Filed: Mar. 29, I972 [2]] App]. No.: 239,374

Related US Application Data [63] Continuation-impart of Ser. No. 22,713, March 25, 1970, abandoned, which is a continuation-impart of Ser. No. 753,860, Aug. 20, 1968, abandoned, which is a continuation-in-part of Ser. No. 668,630, Sept. 18, 1967, abandoned.

[52] US. Cl 252/186, 8/111, 162/78, 252/95, 252/99, 260/610 A, 423/272, 424/130, 424/338 [11'] 3,816,324 June 11, 1974 Primary ExaminerLeland A. Sebastian Assistant Examiner-lrwin Gluck Attorney, Agent, or Firm-John M. Miele [5 7] ABSTRACT A dry oxygen bleaching composition which is useful at relatively low water temperatures is provided. The composition contains a hydrogen peroxide releasing compound and an activating amount of an N-acyl azole of the formulas:

wherein R, individually is hydrogen, alkyl, halogen or nitro; R can be a wide variety of substituted or unsubstituted alkyl, alicyclic or aryl radicls; A is a monoor di-substituted or un-substituted 6'membered aromatic or N-heteroaromatic ring having l-4 nitrogen atoms; and x and y are individually selected from nitrogen and C12,, and at least one of x and y is nitrogen. A typical composition is a mixture of sodium perborate and N-acetyl imidazole in a 1:1 m-ol ratio.

15 Claims, N0 Drawings BLEACIIING COMPOSITIONS CONTAINING A N-ACYL AZOLIE CROSS REFERENCES TO RELATED APPLICATIONS This application is a continuation-in-part of U.S. application Ser. No. 22,713 filed Mar. 25, 1970 now abandoned, which is a continuation-in-part of US. application Ser. No. 753,860, filed Aug. 20, 1968, now abandoned, which in turn is a continuation-in-part of US. application Ser. No. 668,630, filed Sept. 18, 1967, which is now abandoned.

Generally stated, the subject matter of the present invention relates to bleaching compositions. More particularly, the invention relates to improved bleaching compositions containing hydrogen peroxide releasing compounds and activators for such compounds.

BACKGROUND OF THE INVENTION Compositions presently used for bleaching textile materials are generally liquid chlorine-type bleaches, such as sodium hypochlorite. Such liquid chlorine bleaches are generally not stable in aqueous solutions and lose their effective bleaching power under prolonged storage. These chlorine-type bleaches are also difficult to handle in liquid form, are destructive to fabrics during bleaching, and can cause localized overbleaching if brought into direct contact with the fabric in the absence of water.

Because of these shortcomings of liquid chlorine bleaches, and particularly because of the fabric degradation caused by such bleaches, the use of oxygen bleaches for bleaching textile materials has been proposed.

Oxygen bleaches generally comprise hydrogen peroxide releasing organic peroxides and inorganic persalts, such as urea peroxide, alkali metal perborates, or the like. In the use of sodium perborate, for example, the fabric degradation is substantially less than that encountered in the use of sodium hypochlorite bleaches.

Unfortunately, however, the bleaching action of sodium perborate and other oxygen bleaches is inferior to that of sodium hypochlorite bleach at relatively low water temperatures, such as those encountered in modern washing machines (about 50 to 70C.). At water temperatures near boiling around 100C. oxygen bleaches bleach textile fabrics as effectively as chlorine bleaches, but many fabrics cannot withstand water temperatures above about 75C. Thus, this high temperature effectiveness of oxygen bleaches is not particularly helpful either as to these delicate fabrics or as to the use of such bleaches in washing machines.

Since oxygen bleaches are less harmful to textile fabrics and can be used in the form ofa dry powder or tablet, thus eliminating the inconvenience of handling a liquid product, many attempts have been made to formulate oxygen bleaching compositions that provide more effective bleaching action at relatively low water temperatures. These bleaching compositions generally contain a hydrogen peroxide releasing inorganic persalt and an activator that promotes or accelerates the bleaching action of the persalt at low water tempera tures. Examples of prior art activators for oxygen bleaches include tris-(acetyl) cyanurate and tetraacetyl methylenediamine, as well as particular hydrazine deratives as disclosed in British Pat. No. 1,046,251, issued to Deutsche Gold-Und Silber-Scheideanstalt Vormals Roessler.

Most of the oxygen bleaches containing these activators have not proven entirely satisfactory, since they do not achieve a bleaching effectiveness comparable to that of liquid chlorine bleaches at water temperatures of about 50 to C. and because they hydrolyze rapidly during storage.

It is therefore a primary object of this invention to provide new and improved oxygen bleaching compositions that achieve effective bleaching at relatively low water temperatures.

Another object of this invention is to provide new and improved oxygen bleaching compositions that contain a hydrogen peroxide releasing organic peroxide or an inorganic persalt and an improved activator compound.

A further object of this invention is to provide dry oxygen bleaching compositions that: contain a hydrogen peroxide releasing compound and an improved activator and that achieve good bleaching effectiveness in water at relatively low temperatures of from about 50 to 70C., without the destructiveness of chlorine bleaches.

Yet a further object of this invention is to provide dry oxygen bleaching compositions which not only exhibit good bleaching activity at relatively low water temperatures, but also are safer and easier to handle than liquid bleach products, are safe for all fabrics, and are useful for high yield bleaching of groundlwood pulp.

Additional objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention, the objects and advantages being realized and attained by means of the compositions and improvements particularly pointed out in the appended claims.

THE INVENTION To achieve the foregoing objects and in accordance with its purpose, this invention as embodied and broadly described provides a bleaching composition comprising a hydrogen peroxide releasing compound selected from the group consisting of hydrogen peroxide, organic peroxides and inorganic persalts, and an activating amount of an N-acyl azole of formula I or II:

wherein R individually is hydrogen, lower alkyl, bromo chloro, fluoro or nitro; R is (a) alkyl of 1 to 18 carbon nitrogen atoms said substituents being nitro, carboxyl, hydroxyl, alkoxy, bromo, chloro, fluoro, sulfo, cyano or alkyl; and X and Y are individually selected from nitrogen and C-R, and at least one of X and Y is nitrogen.

Compound Revised Ring Index Serial No. triazolo tetrazine 1072 triazolo pyrimidines 1079,1081 triazolo pyridazine 1083 triazolo pyridines 1089,]09 1,1092 benzotriazole I097 imidazo triazine l 159 pyrazolo triazine l 160 pyrazolo pyrimidines 1168.1 I74 pyrazolo pyrazine l l7l pyrazolo pyridazines l l72,l l75 imidazo pyrazine ll76 imidazo pyridazine 1 I77 imiduzo pyrimidines l 179,1 180 pyrazolo pyridines l 186,1 190 imidazo pyridines l l92-l 195 induzole 1209 R is an organic radical and can be any of a wide variety of substituted or unsubstituted alkyl, alicyclic or aromatic carboxylic radical of less than three rings. The alkyl radicals can contain from one to eighteen carbon atoms, but preferably have from one to eight carbon atoms because alkyl radicals having more than eight carbon atoms have only limited solubility in water.

The unsubstituted alkyl radicals which can be represented by R in the above formula may include both saturated and unsaturated radicals and thus include straight or branched chain alkyl radicals such as methyl, ethyl, n-propyl, isopropyl, t-butyl, hexyl octyl, nonyl, tetradecyl, octadecyl, and the like; and unsaturated ethylenic or acetylenic hydrocarbon radicals such as ethenyl, butenyl, tetradecenyl, ethynyl, octadecynyl, and the like.

The substituted alkyl radicals include halo, nitro, and alkoxy substituted alkyl radicals such as methoxymethyl, tri-fluor'omethyl, l-chlorobutyl, l-nitroethyl, and the like.

R can also comprise alicyclic radicals including cycloalkanes, such as cyclobutyl, cyclohexyl, lchlorocyclohexyl, and the like; unsubstituted aromatic carbocyclic radicals of less than three rings, such as phenyl, naphthyl, and the like; and these may also be further substituted with radicals such as hydroxy, alkyl, nitro, halo, alkoxy, and imidazolylcarbonyl-substituted aryl radicals. Exemplary of such substituted carbocyclic aromatic radicals are tolyl, p-nitrophenyl, pmethoxyphenyl, p-chlorophenyl, and the like.

The alkyl substituents on ring A may be the same for R and the alkoxy radicals preferably are lower alkyl (C -C Halo in any of the radicals defined above include chloro, bromo and fluoro.

Illustrative of some specific N-acyl azole compounds which can be used as activators in the bleaching compositions of this invention include:

N-Acetyl lmidazole N-Butyryl lmidazole N-Trimethylacetyl lmidazole N-Benzoyl lmidazole N-Toluoyl lmidazole N-p-Chlorobenzoyl lmidazole N-p-Nitrobenzoyl lmidazole N-p-Methoxybenzoyl lmidazole 2-Ethyl-4-methyl-N-acetyl-imidazole 4-Nitro-N-acetylimidazole N-acetyl-4-cyanobenzimidazole N-acetylbenzimidazole S-Nitrol-acetylbenzimidazole l-Acetyl-5-sulfo-benzotriazole l-Benzoyl-4, 7-dichlorobenzimidazole l-Acetylimidazo [4,5-b] pyridine l-Acetylimidazo [4,5-b] pyrazine The preferred compounds of the invention are those exhibiting the best balance of activity and watersolubility.

Activity is related to the acidity of the carbonyl group attached to R and is therefore enhanced by aromaticity and the presence of electron withdrawing groups in the azole portion of the molecule. Solubility is enhanced by substituents such as those defined by R, and R Among the preferred compounds are l-acetyll H- benzotriazole and especially l-benzoyl-Z- methylimidazole. Other preferred compounds are N- acetylimidazole, N-benzoylimidazole, N-pnitrobenzoylimidazole, and the substituted benzimidazoles of formula II.

The novel bleach activators of this invention (formulas I and II above) can be prepared by several known methods including, for example, the reaction of imidazole with isopropenyl acetate or acetyl chloride to produce N-acetylimidazole in the manner illustrated in the specific examples presented herein.

The oxygen bleaches useful in the bleaching compositions of this invention are hydrogen peroxide, organic peroxides, and inorganic persalts that liberate hydrogen peroxide in water. Examples of organic peroxide bleaching compounds are urea peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, and the like. Exemplary of inorganic persalt bleaching compounds are alkali metal perborates, percarbonates, perphosphates and the like. Mixtures of two or more such bleaching compounds can also be used, if desired.

Sodium perborate is a preferred bleaching compound for use in the bleaching compositions of this invention because of its low cost and ease of handling in dry form, and because it achieves particularly effective bleaching without fabric degradation.

The bleaching compositions of this invention preferably contain the N-acyl azole activating compound and the hydrogen peroxide releasing compound in a mol ratio of about 1 to 1. Since each mol of bleach activator reacts with one mol of thehydrogen peroxide releasing compound, stoichiometric proportions are preferred to achieve full benefit from the activating compound. The ratio of activator to bleach can, of course, be varied widely for varying applications, as desired. Thus, from one to about l.5 moles or even more of the activator may be used per mole of peroxide releasing compound although use of excessive amounts becomes uneconomical and serves no useful purpose.

In an advantageous embodiment of this invention, the bleaching composition comprises an equimolar mixture of sodium perborate and N-acetyl imidazole to provide a bleaching composition having a concentration of 50 ppm active oxygen. Such a composition can be provided in dry powder form and, when used in water, provides and effective laundry bleach for bleaching textiles and other materials at relatively low water temperatures of from about 50 to 70C.

To illustrate the invention more specifically, reference is made to the following examples. These examples illustrate the preparation of the bleach activators and the use of the bleaching compositions of this invention in the bleaching of textiles. These examples are merely illustrative and are not to be understood as necessarily limiting the scope and underlying principles of the invention in any way. All parts and percentages referred to herein are by weight unless otherwise specifically indicated.

EXAMPLE 1 N-acetyl imidazole is prepared by dissolving 78.05 grams (1 mole) of acetyl chloride in 200 ml. of tetrahydrofuran. The acetyl chloride solution is then added dropwise to a solution of 136.16 grams (2 moles) of imidazole in 1,000 ml. of tetrahydrofuran. The reaction mixture is exothermic and is maintained below 40C. in an ice bath to precipitate imidazole hydrochloride during this addition step.

The reaction mixture is then heated under reflux for 2 hours, cooled, and the imidazole hydrochloride filtered off and discarded.

The liquid portion of the reaction product is stripped of solvent leaving white crystals that are recrystallized from tetrahydrofuran to yield 61.25 grams of a white crystalline product. This product is shown by analysis to be N-acetyl imidazole. The product has a melting point of 102 to 103C. and analyzes as follows:

%C %H %N Calculated for N OC H 54.55 5.48 25.44 Found: 54.34 5.33 25.66

EXAMPLE 2 4-Nitro- N-acetyl imidazole is prepared by adding 1.25 ml. of sulfuric acid dropwise to a mixture of 5.66 grams (0.05 mole) of 4-nitro imidazole and 100 ml. of isopropenyl acetate. The reaction mixture is heated under reflux for about two hours, cooled, and then neutralized with anhydrous sodium carbonate.

The liquid portion of the reaction product is decanted and triturated with ethyl ether. Crystals are formed in the ethyl ether layer that are recrystallized from tetrahydrofuran to yield 3.3 grams of a crystalline product shown by analysis to be 4-nitro-N-acetyl imidazole. The product has a melting point of 975 to 98.5C. and analyzes as follows:

'7rC %H %N Calculated for N -,O;,C H 39.02 3.24 27.05 Found: 38.96 3.36 27.14

EXAMPLE 3 N-p-nitrobenzoyl imidazole is prepared according to the procedure of Example 1 by substituting 1 mole of p-nitrobenzoyl chloride for the acetyl chloride used in Example 1. A product having a melting point of 121 to 122C. and shown by analysis to be N-p-nitrobenzoyl imidazole is recovered.

EXAMPLE 4 Preparation of l-Acetyl-lH-benzotriazole A mixture of 10.0 grams (0.09 mole) benzotriazole and 75ml. of acetic anhydride is heated at reflux for 4 hours. Water is then added slowly to decompose the excess acetic anhydride. This is then cooled in an ice bath and filtered to give 6.2 grams of a white crystalline solid. Recrystallization from ethanol alcohol yields long white needles of m.p. 4849C. If in this procedure 5 (or 6) -methylbenzotriazole or a mixture thereof is used in place of benzotriazole, the corresponding methyl substituted product is obtained.

EXAMPLE 5 Preparation of 1-Benzoyl-2-methylimidazole To 200ml. of benzene (reagent grade, dried) is added 16.4 grams (0.2 mole) 2-methy1imidazole and 14.4 grams (0.1 lmole) of benzoyl chloride and this reaction mixture heated to reflux. The byproduct, 2- methylimidazole hydrochloride, begins to precipitate almost immediately. Refluxing is continued for 6 hours. The reaction mass is cooled to room temperature, filtered and the residue washed with benzene. The filtrate is dried over anhydrous magnesium sulfate, treated with actuated charcoal, the benzene removed over a steam bath and the remaining filtrate distilled (b.p. 116l20C at 0.1 to 0.15 mm.). The yield is about 13 grams which is shown to be 99.7 percent pure by vapor phase chromatography.

EXAMPLE 6 A dry oxygen bleaching composition is prepared by mixing 0.33 grams of N-acetyl imidazole, prepared by the procedure of Example 1, and 0.462 grams of sodium perborate. The composition has an equimolar ratio of imidazole to perborate and a concentration of 50 ppm active oxygen.

The bleaching effectiveness of this composition is de' termined by the following test procedure: Thirty-two swatches of desized cotton fabric (5 inches X 5 inches) are stained with tea in the following manner. Five tea bags are placed in 1 liter of water and boiled for 5 minutes. Thereafter, the swatches are immersed in the tea and the boiling is continued for another 5 minutes. The swatches are then wrung out, dried at a high tempera ture, rinsed in cold water and again dried.

Two of the stained cotton swatches are added to a stainless steel Terg-O-Tometer vessel, produced by the U.S. Testing Company. Cut-up pieces of white terry cloth toweling are added to provide a typical household washing machine water-to-cloth ratio of about 20 to l.

The bleaching composition is then added to each vessel along with a predetermined quantity of sodium carbonate or standard sulfuric acid to obtain the desired pH. The Terg-O-Tometer is operated at cycles per minute for 15 minutes at a temperature of 50C. At the end of the cycle, the swatches are removed, rinsed with cold water, and ironed dry.

Reflectance readings of the swatches are taken both before and after the cycle using a Hunter Model D-40 Reflectometer with a blue filter. Each swatch is read twice (warp and fill) on each side, with a backing of three similarly stained swatches. Fluorescent effect is excluded from all readings.

The reflectance readings are averaged and the percent stain removal is obtained in accordance with the following formula:

Total percent stain removal=[Reflectance after bleaching]-[Reflectance before bleaching (stained) ]X l Reflectance before staining]-[Reflectance beforebleaching (stained)] The bleaching composition of this example removes an average of 60 percent of stain from the swatches, as

measured by this formula.

EXAMPLE 7 A dry bleaching composition, similar to the bleaching composition of Example 6, is prepared by mixing together 0.462 grams of sodium perborate and 0.52

' grams of N-ben ioyl imidazole. The composition has an that 73 percent of the stain is removed by treatment with the bleaching composition of this example.

EXAMPLE 8 A dry bleaching composition, similar to the bleaching composition of Example 6 is prepared by mixing together 0.462 grams of sodium perborate and 0.67 grams of N-p-nitrobenzoyl imidazole. This composition has an equimolar ratio of perborate to imidazole and a concentration of 50 ppm active oxygen.

Cotton swatches are stained according to the procedure of Example 6 and the bleaching effectiveness of the composition is determined by the test procedure of Example 6.

Reflectance readings of the cotton swatches show that 65 percent of the stain is removed by treatment with the bleaching composition of this example.

EXAMPLES 9-29 tional activator compounds in Examples 9-29. The

composition all have an equimolar ratio of'perborate to the N-acyl azole compound, and a concentration of 50 ppm active oxygen.

Examples 24-29 are carried out for comparative purposes to illustrate the effectiveness of the bleaching compositions of this invention in modern automatic washing machines operating at relatively low water temperatures of about 50 to 70C. The comparative bleach compositions have a concentration of 50 ppm active oxygen or active chlorine depending on the bleach used in each example.

. The testing procedure of Example 6 is repeated with the newly formed bleach compositions listed in Table l, with the stained swatches being added to a stainless steel Terg-O-Tometer containing water at a temperature of 50C.

Reflectance readings of the swatches are taken both before and after the cycle, and the percent stain removal achieved by the various bleaching compositions is measured in accordance with the above formula. The results are reported in Table l below which tabulates the results listed in examples 6, 7 and 8 plus the results of the additional compositions from examples 9-23 and 24 through 29.

TABLE 1 Example No. Bleaching Composition Percent Stain Removal 6 Sodium Perborate N- 60.0

Acetyl lmidazole 7 Sodium Perborate N- 73.00

Benzoyl lmidazole 8 Sodium Perborate N-p- 65.00

v Nitrobenzoyl lmidazole 9 Sodium Perborate N-propionyl 55.2

imidazole l0 Sodium Perborate N-Butyryl 57.6

lmidazole l 1 Sodium Perborate N-Trimethyl- 41.0

acetyl imidazole l2 7 Sodium Perborate N-Octanoyl 48.3

' lmidazole 13 Sodium Perborate N-Palmitoyl 46.0

lmidazole l4 Sodium Perborate N-Toluoyl 6l.0

lmidazole 15 Sodium Perborate Np-Chloro- 62.0

benzoyl lmidazole l6 Sodium Perborate N-p-Methoxy- 58.0

henzoyl lmidazole 17 Sodium Perborate N-Terephthal- 46.0

oyl Diimidazole 18 Sodium Perborate 2-Ethyl- 35.7

4-Methyl-N-Acetyl lmidazole 19 Sodium Perborate 4-Nitro- 52.0

N-Acetyl imidazole 20 Sodium Perborate 4Bromo- 49.4

N-Acetyl lmidazole 21 Sodium Perborate N-Acetyl- 35.0

benzimidazole 22 Sodium Perborate l-Acetyl-IH- 84.4

benzotriazole 23 Sodium Perborate l-Benzoyl-2- 90.5

methylimidazole 24 Sodium Hypochlorite (CLOROX) 74.0

25 Sodium Perborate l6.0

26 Sodium Persulfate l9.0

27 Hydrogen Peroxide 19.0

28 Sodium Perborate TACA 52.0

29 Sodium Perborate Solium 2 53.0

1 tris-(acetyl) cyanurate activator for the oxygen bleach, produced by FMC Corp. and used at recommended use levels.

2 tetraacetyl methylenediamine activator for the oxygen bleach, produced by Lever Bros. and used at recommended use levels.

EXAMPLE 34 The dry bleaching composition of Example 6 is dissolved in an aqueous solution and applied at normal room temperature to various substrates such as bathroom floors, kitchen counter tops and hospital rooms to control various microbes or germs. The composition is particularly effective because the major antimicrobial or germicidal component, the active oxygen, is released at lower temperatures than is usual with peroxide-type germicides.

The compositions of the invention, containing approximately stoichiometric proportions of N-acyl azole and hydrogen peroxide releasing compound, are germicidally effective at concentrations of about 5 to 200 parts per million, preferably about 10 to 50 parts per million, based on the amount of active oxygen made available by the compositions.

The treatment of swimming pool water and swimming pool surfaces with the compositions of the invention is especially efficacious since the usually lower temperatures of these environments prevent effective 'use of other antimicrobial agents. A related utility is the treatment of water-supplies to render the same fit for human consumption or for industrial use, such as the sanitization of field water for consumption by military personnel or the treatment of industrial process water so it can be reused in industrial processes or by the surrounding community. The compositions also may be employed in admixture with detergents for use as home or industrial germicidal detergents.

What is claimed:

1. A bleaching composition consisting essentially of hydrogen peroxide or a hydrogen peroxide releasing compound selected from the group consisting of organic peroxides and inorganic persalts; and an activating amount of an N-acyl azole of the formulas:

a. R is individually hydrogen, lower alkyl, bromo,

chloro, fluoro or nitro; b. R; is

i. alkyl of one to eighteen carbon atoms ii. bromo, chloro, fluoro, nitro or alkoxy substituted (Cr-C13). iii. alicyclic iv. aromatic carbocyclic radical of less than three rings v. hydroxyl, alkyl, nitro, bromo, chloro, fluoro, lower alkoxy or imidazolylcarbonyl substituted phenyl or naphthyl c. A is a monoor disubstituted or unsubstituted 6- membered aromatic or N-heteroaromatic ring containing one to four nitrogen atoms, said substituents being nitro, carboxyl, hydroxyl, alkoxy, bromo, chloro, fluoro, sulfo, cyano or alkyl; and d. X and Y are individually selected from nitrogen and CR,, and at least one of X and Y is nitrogen,

the activating amount of the N-acylazole in the composition being at least one equivalent of the N- acylazole for each equivalent of the hydrogen peroxide releasing compound. 2. The composition of claim 1 wherein the N-acyl azole is an N-acyl imidazole.

3. The composition of claim 2 wherein the hydrogen peroxide releasing compound is an alkalLmetal persalt.

4. The composition of claim 3 wherein the mole ratio of the imidazole to the persalt is about 1 to l.

5. The composition of claim 2 wherein the imidazole is N-acetyl imidazole.

6. The composition of claim 5 comprising the persalt sodium perborate.

7. The composition of claim 2 wherein the imidazole is N-benzoyl imidazole.

8. The composition of claim 7 comprising the persalt sodium perborate.

9. The composition of claim 2 wherein the imidazole is N-pnitrobenzoyl imidazole.

10. The composition of claim 2 wherein the imidazole is l-acetyll H-benzotriazole.

11. The composition of claim 10 comprising the persalt sodium perborate.

12. The composition of claim 2 wherein the imidazole is l-benzoyl-2-methylimidazole.

13. The composition of claim 12 comprising the persalt sodium perborate.

14. A process for bleaching fabrics and wood pulp which comprises contacting said fabrics or wood pulp in an aqueous medium with the composition of claim 1.

15. A process for controlling microbes which comprises contacting an environment subject to microbial growth with the composition of claim 1.

l l =l 

2. The composition of claim 1 wherein the N-acyl azole is an N-acyl imidazole.
 3. The composition of claim 2 wherein the hydrogen peroxide releasing compound is an alkali-metal persalt.
 4. The composition of claim 3 wherein the mole ratio of the imidazole to the persalt is about 1 to
 1. 5. The composition of claim 2 wherein the imidazole is N-acetyl imidazole.
 6. The composition of claim 5 comprising the persalt sodium perborate.
 7. The composition of claim 2 wherein the imidazole is N-benzoyl imidazole.
 8. The composition of claim 7 comprising the persalt sodium perborate.
 9. The composition of claim 2 wherein the imidazole is N-p-nitrobenzoyl imidazole.
 10. The composition of claim 2 wherein the imidazole is 1-acetyl-1H-benzotriazole.
 11. The composition of claim 10 comprising the persalt sodium perborate.
 12. The composition of claim 2 wherein the imidazole is 1-benzoyl-2-methylimidazole.
 13. The composition of claim 12 comprising the persalt sodium perborate.
 14. A process for bleaching fabrics and wood pulp which comprises contacting said fabrics or wood pulp in an aqueous medium with the composition of claim
 1. 15. A process for controlling microbes which comprises contacting an environment subject to microbial growth with the composition of claim
 1. 